Electrical systems associated with aircraft and other vehicles may have a plurality of electrical subsystems, each having one or more electrical power distribution systems. Such electrical power distribution systems may include one or more power distribution cards mounted vertically to the electrical system in a rack-like manner. Such power distribution cards may include one or more printed circuit boards having one or more switching devices configured to control current flow to a load associated with the electrical system. The printed circuit boards may further include one or more control devices configured to control operation of at least one switching device.
Conventional power distribution cards may have a layout configuration wherein one or more switching devices are located in close proximity to a corresponding control device. For instance, a switching device and a corresponding control device may be coupled to the power distribution card as part of a prefabricated solid state power controller (SSPC) “module.” FIG. 1 depicts an example conventional power distribution card 100. As shown, card 100 includes SSPC blocks A-L, routing device 102, and card controller 104. Card 100 further includes connector 106 configured to connect card 100 to an electrical system. Each SSPC block A-L can be associated with one or more electrical subsystems. In particular, each SSPC block A-L can be configured to regulate current flow to a load associated with the corresponding electrical subsystem. As shown, each SSPC block A-L includes two power switching devices (e.g. power FETs), a current sensor, and control logic located in close proximity to each other.
During operation of card 100, the configuration of the SSCP blocks A-L can provide a generally even temperature distribution across card 100. Heat dissipation associated with the power FETs may be proportional to the square of the load current, while heat dissipation associated with the control logic may remain generally constant. Accordingly, when the load current associated with the power FETs is a high load current, the heat generated by the current flow will be much greater than that generated by the relatively low power control logic. In this manner, the control devices may experience an increased local temperature environment, which may reduce the reliability or cause unpredictable behavior in the control devices. For instance, if the average operating temperature of the control logic exceeds the specified maximum operating temperature of the control logic, the control logic may fail and/or act in an unpredictable manner.